*{
    margin: 0;
    padding: 0;
}
.finite-state{
    position: relative;
    width: 200px;
    height: 200px;
    background: #000;
}
.btn{
    width: 120px;
    height: 50px;
    margin: 50px 20px;
}
.btn1{
    background-color: #999999;
}
.btn2{
    background-color: #334444;
}
.btn3{
    background-color: #222222;
}